The present invention relates to an apparatus for closing containers. Such apparatuses, which are hereinafter also referred to as closing machines, have long been known in the prior art. They serve to close containers, for example plastic containers, with closures. For example, screw closures are screwed onto the containers. In many applications, it is necessary to this end that the containers are guided through a sterile chamber and in this way can be closed in a sterile environment. In addition, however, the present invention is also applicable to other apparatuses for treating containers, such as for example filling installations, sterilisation devices, cleaning units, transport devices and the like.
U.S. Pat. No. 7,334,380 B2 discloses an apparatus for screwing closures onto containers. The apparatus comprises a rotatable spindle which has a closing head at one end and which is connected at the other end to a coupling element, wherein this coupling element comprises a magnetic core and a magnetic bell, which cooperate with one another.
Also provided is a displacement device which can displace the magnetic bell and the magnetic core relative to one another between a position in which they are in engagement with one another and a position in which they are uncoupled from one another. In this way, a coupling or uncoupling is achieved by using a magnetic coupling. EP 0 863 106 A1 likewise describes a closing apparatus. In this case, a closing head is arranged on a rotatable spindle. Provided at the upper end of this spindle is a plurality of permanent magnets which are in each case arranged with alternating poles next to one another. Also provided is a rotation-generating means, on which likewise a plurality of permanent magnets is arranged, wherein a cooperation between these rotating elements also brings about a rotation of the spindle.
EP 1 186 873 discloses a magnetic coupling device for transmitting and measuring torques, which comprises a first and a second body which rotate in relation to an axis.
DE 203 01 532 describes an electric motor drive. This drive comprises a stator extending over a sector of the circumference and a rotor provided with permanent magnets, wherein in each case run-out zones with run-out sides facing towards the rotor are provided at the peripheral ends of the stator, which run-out zones, starting from the curved inner side of the stator parallel to the outer side of the rotor, are at an increasing distance from the outer side of the rotor along their circumferential extent.
DE 10 2006 039 090 A1 discloses a drive for rotary machines. This drive comprises a stationary machine part and a rotatable machine part, wherein a collar having a plurality of magnets is provided around the circumference on one machine part and at least one corresponding stator which covers just a partial sector of the collar is arranged on another machine part.
In the case of such closing apparatuses, it is usually necessary that the closing head is not only rotated but rather also is raised and lowered. For this reason, in the prior art, sealing elements such as shaft sealing rings for example are often provided between the areas located outside the sterile chamber and the areas located inside the sterile chamber. In addition, it is also known to insert a so-called water lock for sealing purposes between the rotatable and stationary parts. Furthermore, it is known that in the case of standard filling machines the starwheels are driven by means of toothed wheels on the starwheel column, wherein these toothed wheels are in turn connected to the main drive.
However, such connections between the sterile chamber and the outside environment usually represent weak points of such closing machines or also of other installations for treating containers.
The object of the present invention is therefore to provide an apparatus for closing containers which at least reduces the need for sealing devices between the sterile chamber and the area located outside the sterile chamber.